The research described in this proposal will continue the examination of infant visual information processing and how that processing changes over age. The research is motivated, in part, by a developmental view that assumes infants at all ages process relational information, but that the types of relations and the types of units involved in those relations change over age. In short, a hierarchical developmental progression has been proposed in which infants at first can process simple relations used to produce elementary features or shapes; later, the relationships between those features are processed to produce a complex pattern or object; and, still later, the relationships between objects are processed to produce meaningful events. Most of the evidence supporting such a progression has come from studies using two-dimensional static patterns. A main goal of the proposed project is to extend these basic findings with more dynamic and realistic objects and events. Two new procedures specifically designed to investigate infants' processing of objects and events will be used: Both involve the assessment of infant habituation and dishabituation. In one, infants will be shown either videotaped recordings of real events or computer animated simulations of those events. In the other, infants will be allowed to visually and manually examine real objects. Sixteen new experiments are described and several others are suggested that will be conducted over a period of 5 years. These studies will examine, in depth, two significant, but understudied, aspects of infant perceptual and/or cognitive development: How infants process causal relations, and how they process the relationship between an object's structure and its function. Developmental changes in these processes also will be explored. The experiments on causal relations will investigate: 1. whether infants tie the causal action to the agent, the recipient, or both; 2. when infants can first categorize causal relations; 3. when they can make causal inferences; 4. and what principles or rules they use to determine whether or not an event is causal. The experiments on infants' processing of the relation between an object's structure and function will examine: 1. when infants can correlate an object's structure with its function; 2. whether producing an object's function is more difficult to process than just observing that function; 3. whether simple functions like the direction of movement can be processed earlier than other functions; and 4. whether verbal labels first become associated with an object's structure, its function, or both.